moffatt



(No Model.) 2 Sheets-Sheet 1.

R. R. MOFFATT Sz S. OHICHESTER.

ELECTRIC LAMP.

No. 245,309.. i Patented Aug. 9,1881.

(No Model.) 2 Sheets-Sheet 2.

R. R. MOFFATT 8v S. CHIOHESTER.

ELECTRIC LAMP.

Patented Aug. QQSL UNITED STATES PATENT OFFICE.

RICHARD B. MOFFATT AND SYLVESTER GHICHESTEB, OF BROOKLYN, N. Y.

ELECTRIC LAM P.

SPECIFICATION forming part of Letters Patent No, 245,309, dated August9, 1881.

Application tiled March 2l, 1881.

.To all whom it may concern Be it known that we, RICHARD R. MOFFATT andSYLvEs'rER CHroHEs'rEE, both ofthe city of Brooklyn, in the county ofKings and State of New York, have invented certain Improvements inElectric Lamps; and we do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it pertains to make and use it,reference being made to the accompanying drawings, which forni part ofthis specification.

Our invention relates to devices for regulating the distance between thepoints ot the electrodes in what is termed a point-to-poiiit electriclamp;77 and it consists in a novel. arrangement of electro-inagnetslocated in the main circuit combined with electro-magnets located in ashunt or derived circuitiii such a manner that the slightest change inthe resistance of the arc will cause the electro-magnets to operatemechanism which will produce a sutlicieiit feed lniovement ofl theelectrodes as they are consumed, to keep them always at the properdistance apart for the production of light ol' a maximum intensity.

In the drawings, Figure l is a front elevation ot' a device embodying`our invention, the lower portion of which is shown partly in section.Fig. 2 represents a plan ot' the upper part of the same. Fig. 3represents a plan view of the upper part of the same with theelectro-magnetsremoved, and showin gthe tilt; ing armature in position.Fig. il is a side view, showing the tilting armature in position. Fig. 5is a sectional view of the carbon holder and tube, illustrating themanner ot' its operation.

Similar letters of reference in the several iigures indicate like parts.

In the drawings, A is a plate ot' wood, which, with the metal pieces a aand a a', forni the frame ot' the lamp.

B is an electro-magnet,which is provided with a hollow core, withinwhich is located a carbon-holder rod c. On the upper end of the rod c issecured the iron armature B. The rod c is capable of a longitudinalmovement within the magnet B. A set-screw nut, d, Workingnear the lowerextremity of the rod (No model.)

c, regulates the movement of the rod, and a small spiral spring, c,tends to force the rod c upward when the electric circuit is broken. Thearmature B' moves with the rod, and when the electric circuit iscomplete the magnet B will draw thc armature B', the lower carbon, andthe rod downward, thus separating the points ot` the electrodes to formthe are.

M is an electro-magnet, which is secured to one arni ot' a yoke, 7i.,the latter being secured to a metallic tube, F. On the other arni ot`the yoke li is mounted an electro-magnet, N. rlliis magnet is soarranged that it can be ailjusted by means of a screw-rod, t', and thetwo screw-nuts fi' fi. The armatures ot' these electro-magnets M and Nare iirmly secured together by a noii-iiiagiietic material, and arepivoted to standards g g, as shown in Figs. 3 and 4, in such a mannerthat the armatures 7i; and L will each be influenced by the magneticforce ot' both the electro-magnets lll and N. These magnets are so wound(or connected up) with wire that the electric currentl passing iii themwill cause the poles to be ot' like nature in each bobbiii or helix thatfaces (and acts upon) the same armature. For example, the armature l;will have the north pole of the magnet M acting' upon one end and thenorth pole ot' the magnet N acting upon its other end, while the sameeffect takes place with the south poles ot' the magnets M and N upon thearmature lt. The magnet M is placed in the main circuit, which conveysthe electric current through the arc, and the magnet N, which is madeot' tine insulated wire having comparatively great resistance, islocated in a shunt or derived circuit.

p is a tube the lower end ot' which carries a carbon-holder. This tubeis arranged to move within the large tube F, in the upper part of whichare located small pulleys.

XV is a weight, to which cords or chains are attached, which, extendingupward and over the pulleys, are iliade fast to the tube p. rIhe weightl tends to couiitcrbalaiice the weight ot the tube p, the latter havinga slight preponderance, thus causing it to move slowly downward by itsgravity. The tube Fis secured at its lower end to the plate A, as shownin Fig. 5.

'SOO

A lever-brake, s, is located as shown, one end of which rests againstthe tube p. A rod, s', extends from the lever to the armatureframe. Eachend of the rod enters a recess, which keeps it in position.

t is a set-screw for adjusting the movement of the tilting armature.

The operation of our invention is as follows: When the electric circuitis made the current enters the binding-post through the ma'gnet M, intothe yoke and tubes F and p; Jthence through the carbons, the magnet B,and frame to the binding-post in its passage. Thus it causes the magnetM to attract the tilting armatures`7c kf, raising the ends nearest tothe magnet M and causing the other ends to be depressed, which, in turn,presses upon the rod s and lever s, thereby preventing the movement otlthe tube p, (and the carbon attached thereto.) At the same time thearmature B is drawn down by the magnet B, taking with it the lowercarbon, thus separating the electrodes, when the arc will appear. Aportion of the current passes from the bindingpost marked through themagnet N, to the binding-post marked (said magnet N having highresistance, as described.) As the carbons are consumed the size ot' thearc increases, and with it the resistance to the electric currentincreases, and the attractive force of the magnet M is lessened. At thesame time the magnetic power of the magnet N is increased in proportionto the increase ot' resistance in the are, and its action on thearmature is to charge the extreme end thereof-wiz., the end ofthearmature that is in close proximity to the poles of the magnet M-withmagnetism of alike or similar nature,thus causing the action ot'repulsion, which tends to force the tilting armature down upon the endofthe set-screw t, and raising the other end ot the armature from therod s', thus relieving the pressure of the lever-brake s upon the tube19, when the latter moves downward by its gravity until the distancebetween the carbon points is lessened, and the resistance in theelectric circuitis also decreased when the magnetic force ot' the magnetM is increased and that of the magnet N is decreased, thus changing thepreponderance ot' like polarity in the armature to the other endthereof, and its action of repulsion upon the magnets is reversed, againdepressing the armature upon the rod s', lever s, and tube p, holdingthe latter from moving. This action ot' the magnets M and N upon thearmature, acting upon the principle of similar poles repellin g eachother, is so sensitive in its action through the agency of the tiltingarmature, (the movement of which is so slight,) as described, that thefeeding of the carbons and the size and resistance in the arc areregulated automatically' with the best results for the production oflight of a maximum intensity.

By means ot screw-nuts i t' the-resistantmagnet N may be adjusted byincreasing or decreasing its distance from the armature, so as to keepany desired arc.

This arrangement of magnets and tilting armature for operating andregulating the working of an electric lamp may be modified in itsvarious details without departing from its general principles; and we donot limit ourselves to the repulsive properties ot' the magnets M and N,acting upon and by means of an armature, for the purpose specied, as theproperties ot' attraction as well as repulsion can be successfullyutilized for the same end by simply mounting or arranging the tiltingarmature upon its pivots in such a Inanner that the armature t: will beunder both poles ot one magnet and the other armature under the poles ofthe other magnet. For this purpose we have shown in Figs. 3 and 4provisions m, in which the pivots that support the tilting armature maybe inserted to operate. In this case the armatures k and 7c' will occupya position.parallel with the oentral line ot' the pivots and at rightangles to that shown in the drawings, while the position of the magnetsM and N will not be changed.

It desired, the weight IV may be a tube, and made to occupy a spacebetween the tubes F and p, the latter passing through the tubeweight.

By the use ot a chain-connection between the tube p and thecounter-weight W said chain in its entirety being` of a less weight thanthe carbon, an element ol' compensation enters into the operation, whichcauses the preponderance in the tube p and carbon to be nearly the same,notwithstanding the loss of weight by the consumption ol"l the carbon.This is caused by the weight of chain gradually decreasing on one sideot' the pulleys and increasing the weight on the other side, thuscompensating for the loss in carbon by consulnption.

The magnets M and N may be axial magnets with movable iron cores.

Having thus fully described the nature, construction, and operation ofour invention, what we claim as new, and desire to secure by LettersPatent, is I 1. In an electric lamp, the combination ot' theelectromagnets B and M, located in the main circuit, and theelectro-magnet N,located in a shunt-circuit, for the purpose of formingand regulating the arc, substantially as herein specified.

2. In an electric lamp, the combination of the electro-magnets M and N,the tilting armature K, 7o' the carbon-rod p, and mechanism to check andregulate the feed of the carbon, substantially as herein specified.

3. In an electric lamp, the combination of the electro-magnet M, locatedin the :main circuit, and the electro-magnet N, located in ashunt-circuit, said magnets having poles of ICO IOS

like nature acting upon the same armature, feed oi' t-he carbon,substantially es herein substantiallynsand for the purpose specitied.specified.

4. Iwan/ electric lamp, the combination of R P MOFFATT theelectro-magnets M and N, the tilting ztrw', w 5 mature 7c 7c', thecarbon-rod 11, and the lever- SYL ESTER GHHJHESEER brake s, constructedsubstantial] y as described, W'itnesses: so that the action of magneticattraction and S. R. KNIFFIN, repulsion will act to check and regulatethe E. M. HERRING.

